1. Field of the Invention
This invention relates to electrical connectors and, more particularly, to interconnection systems providing an increased number of circuits by means of multiple rows of contacts, where it is desirable to maintain compatibility with components having fewer interconnect circuits.
2. Cross-Reference to Related Applications
U.S. Pat. Nos. 5,096,435 and 5,197,887, and copending application Ser. No. 07/990,812 describe high density edge card connection apparatus which includes a connector configured to receive a portion of a daughter card in a central slot, and a daughter card having two rows of contact pads adjacent to an insertion edge, on each side of the card. The connector has two rows of contact springs on each side of the central slot, extending into the central slot to contact the associated rows of contact pads on an inserted daughter card, supported in position by an insulative housing, and extending outward therefrom to be soldered to various circuits in a mother board.
These applications describe solutions for the problems associated with increasing the density of an interconnection system having a single row of contact pads on each side of the daughter card and a single row of contact springs on each side of the central slot of the connector, wherein the increase in density is made by adding a second row of contact pads on each side of the card and a second row of contact springs on each side of the central slot in the connector, and wherein it is necessary to maintain interchangeability between both cards and connectors of the new and old types. This concept is applied where forethought about an eventual need to increase the density of the interconnection in this way has not occurred; daughter cards of the old type have various conductive surfaces in the space where the new rows of contacts must be placed. To allow the use of such old types of cards in the new connectors, means must be provided to prevent contact between the new, additional rows of contact springs and the adjacent surfaces of such a card as it is inserted into the connector.
In U.S. Pat. No. 5,197,887, interposing means are provided to hold these contact springs out of contact with the card in this situation. In a first embodiment, such interposing means consist of insulative camming surfaces slid into place over this space in the card before the card is inserted into the connector. In a second embodiment, such interposing means consists of an interposer pivotably mounted in the connector at each side of the central slot, to be rotated into a position holding the new, additional rows of contact springs out of electrical contact with the card whenever an old type of daughter card is inserted.
In U.S. Pat. No. 5,096,435 and copending application Ser. No. 07/990,812, the new rods of contact spring are formed so that they hold themselves out of contact with an inserted daughter card. The insertion of a card of the new type causes the sliding of an actuator which moves these springs into contact with the card.